// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// A helper function for using JsTemplate. See jstemplate_builder.h for more
// info.

#include "ui/base/webui/jstemplate_builder.h"

#include "base/json/json_file_value_serializer.h"
#include "base/json/json_string_value_serializer.h"
#include "base/logging.h"
#include "base/strings/string_util.h"
#include "ui/base/layout.h"
#include "ui/base/resource/resource_bundle.h"
#include "ui/resources/grit/webui_resources.h"

namespace webui {

namespace {

    // Appends a script tag with a variable name |templateData| that has the JSON
    // assigned to it.
    void AppendJsonHtml(const base::DictionaryValue* json, std::string* output)
    {
        std::string javascript_string;
        AppendJsonJS(json, &javascript_string);

        // </ confuses the HTML parser because it could be a </script> tag.  So we
        // replace </ with <\/.  The extra \ will be ignored by the JS engine.
        base::ReplaceSubstringsAfterOffset(&javascript_string, 0, "</", "<\\/");

        output->append("<script>");
        output->append(javascript_string);
        output->append("</script>");
    }

    // Appends the source for load_time_data.js in a script tag.
    void AppendLoadTimeData(std::string* output)
    {
        // fetch and cache the pointer of the jstemplate resource source text.
        base::StringPiece load_time_data_src(
            ResourceBundle::GetSharedInstance().GetRawDataResource(
                IDR_WEBUI_JS_LOAD_TIME_DATA));

        if (load_time_data_src.empty()) {
            NOTREACHED() << "Unable to get loadTimeData src";
            return;
        }

        output->append("<script>");
        load_time_data_src.AppendToString(output);
        output->append("</script>");
    }

    // Appends the source for JsTemplates in a script tag.
    void AppendJsTemplateSourceHtml(std::string* output)
    {
        // fetch and cache the pointer of the jstemplate resource source text.
        base::StringPiece jstemplate_src(
            ResourceBundle::GetSharedInstance().GetRawDataResource(
                IDR_WEBUI_JSTEMPLATE_JS));

        if (jstemplate_src.empty()) {
            NOTREACHED() << "Unable to get jstemplate src";
            return;
        }

        output->append("<script>");
        jstemplate_src.AppendToString(output);
        output->append("</script>");
    }

    // Appends the code that processes the JsTemplate with the JSON. You should
    // call AppendJsTemplateSourceHtml and AppendJsonHtml before calling this.
    void AppendJsTemplateProcessHtml(
        const base::StringPiece& template_id,
        std::string* output)
    {
        output->append("<script>");
        output->append("var tp = document.getElementById('");
        output->append(template_id.data(), template_id.size());
        output->append("');");
        output->append("jstProcess(loadTimeData.createJsEvalContext(), tp);");
        output->append("</script>");
    }

    // Appends the source for i18n Templates in a script tag.
    void AppendI18nTemplateSourceHtml(std::string* output)
    {
        base::StringPiece i18n_template_src(
            ResourceBundle::GetSharedInstance().GetRawDataResource(
                IDR_WEBUI_I18N_TEMPLATE_JS));

        if (i18n_template_src.empty()) {
            NOTREACHED() << "Unable to get i18n template src";
            return;
        }

        output->append("<script>");
        i18n_template_src.AppendToString(output);
        output->append("</script>");
    }

} // namespace

std::string GetI18nTemplateHtml(const base::StringPiece& html_template,
    const base::DictionaryValue* json)
{
    std::string output(html_template.data(), html_template.size());
    AppendLoadTimeData(&output);
    AppendJsonHtml(json, &output);
    AppendI18nTemplateSourceHtml(&output);
    return output;
}

std::string GetTemplatesHtml(const base::StringPiece& html_template,
    const base::DictionaryValue* json,
    const base::StringPiece& template_id)
{
    std::string output(html_template.data(), html_template.size());
    AppendLoadTimeData(&output);
    AppendJsonHtml(json, &output);
    AppendI18nTemplateSourceHtml(&output);
    AppendJsTemplateSourceHtml(&output);
    AppendJsTemplateProcessHtml(template_id, &output);
    return output;
}

void AppendJsonJS(const base::DictionaryValue* json, std::string* output)
{
    // Convert the template data to a json string.
    DCHECK(json) << "must include json data structure";

    std::string jstext;
    JSONStringValueSerializer serializer(&jstext);
    serializer.Serialize(*json);
    output->append("loadTimeData.data = ");
    output->append(jstext);
    output->append(";");
}

} // namespace webui
